Area Rug Size Calculator
Find the right area-rug size for a room by leaving an even border of bare floor around it, then snap to the nearest standard rug size.
How it works
Rug length = room length − 2 × border · Rug width = room width − 2 × border (border in feet)
The classic rule is to leave a consistent strip of bare floor — roughly 12 to 24 inches — around all four sides of the rug so the flooring frames it evenly. Subtracting twice the border (one strip on each side) from each room dimension gives the largest rug that keeps that frame. Because rugs are sold in fixed sizes, the result is then rounded down to the nearest stock size so the border never disappears.
Worked example
A 15 × 12 ft room with an 18-inch border loses 2 × 18 = 36 inches (3 ft) on each dimension, leaving room for a 12 × 9 ft rug — which happens to be a standard stock size.
Frequently asked questions
How much floor should show around a rug?
Designers usually leave 12 to 24 inches of bare floor on each side. In a small room lean toward 12 inches so the rug does not look lost; in a large room 18 to 24 inches keeps the border in proportion.
Should the rug go under the furniture?
In a living room, aim to fit at least the front legs of every seat on the rug. For a dining room the rug should extend about 24 inches past the table on every side so chairs stay on it when pulled out.
What are common standard rug sizes?
The most common stock sizes are 5×3, 8×5, 9×6, 10×8, 12×9 and 15×12 feet. This calculator rounds your ideal size down to the nearest of these so the bare-floor border is preserved.
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This calculator is for educational purposes. Double-check important results before acting on them.